Book/Report

FZJ-2019-04506

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Assoziierte Strangeness-Erzeugung an der Produktionsschwelle in der Reaktion pp $\rightarrow$ pK$^{+}\Lambda$ am Experiment COSY-11 mit einer optimierten Strahloptik

Schepers, G. (Corresponding author)FZJ*

1998
Forschungszentrum Jülich, Zentralbibliothek, Verlag Jülich

Please use a persistent id in citations: http://hdl.handle.net/2128/22627

Report No.: Juel-3586

Abstract: Using the experimental setup ofthe COSY-11 facility the energy dependence of the total cross section for the pp $\rightarrow$ pK$^{+}\Lambda$-reaction was measured in the threshold region covering the excess energy range up to 7 MeV. The slope of the measured cross sections is described well by model calculations, but the rate is underestimated by a factor of two to three. A special and precise determination of the proton beam momentum of the COSY-synchrotron using the measured data themselves was performed. Investigations of the differential cross sections Show that s-wave production is dominant in the pp $\rightarrow$ pK$^{+}\Lambda$-reaction near threshold. By comparing model phase-space Dalitz plot occupations with the experimental ones, constraints on the spin-averaged $\Lambda$p scattering lenght and effective rang have been obtained. The low energy $\Lambda$p scattering parameters could be determined when combining the position of the virtual bound state in the $\Lambda$p system with data from elastic $\Lambda$p scattering measurements, together with the fact that the hyperdeuteron is not bound. A major intension was given for the development and installation of a special magnet optics for the COSY-synchrotron to get optimal proton beam conditions for the COSY-11 experiment. Varying the focussing and defocussing strength of the quadrupol in both of the arcs of the cooler ring the dimensions of the proton beam was reduced to the size of the Cluster target beam. The change of the optics from the normal COSY one to this special COSY-11 optics combines a hight resolution measurment due to the srnall size of the reaction zone with a high luminosity - due to the maximized overlapp of proton beam and target.

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Contributing Institute(s):

1. Publikationen vor 2000 (PRE-2000)

Research Program(s):

1. 899 - ohne Topic (POF3-899) (POF3-899)

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